It is the usual practice in laying a plastic pipeline to apply the bonding adhesive to the end of one pipe, and then to insert that end into the end of a second pipe and, after the bond has formed, to move on to the next joint in the pipeline, and repeat the operation. This prior art approach, however, is awkward and time consuming.
In the practice of the present invention, the entire pipeline can be layed out with each length of pipe fitted into the adjacent pipe prior to the application of the adhesive. Then, a single worker may go from joint-to-joint with an adhesive gun, and quickly and efficiently inject the adhesive into each joint to cause each of the pipes in the pipeline to be bonded to the adjacent pipe. This is achieved, in each instance, merely by inserting the gun into the entrance port at the end of each length of pipe, injecting the adhesive through the entrance port into the internal channel, and continuing to inject the adhesive until it is discharged through the exit port.
As pointed out above, during each injection operation, a rupturable film in the exit port will remain in place until the pressure of the adhesive in the internal channel is high enough to assure that a complete ring of adhesive is forced firmly against the outer surface of the inserted end of the adjacent pipe. The film will then break permitting excess adhesive to flow out through the exit port. As also pointed out, this film is initially pierced, to provide a small air hole, so that all air within the channel may be caused to bleed out through the hole.